BANNARI AMMAN INSTITUTE OF TECHNOLOGY

SATHYAMANGALAM

Department of EEE & EIE

Class S8 EEE A & B, S8 EIE

Subject Code 11N016

Subject RENEWABLE ENERGY SOURCES Prepared By Dr. A. Jagadeesan, P.Karuppusamy, S. Sudhahar

Time: 75min

Lesson. No Unit 3 -3/5

1.

Content List: squirrel cage and doubly fed induction generators.

2.

Skills Addressed: Reading, Questioning, Drawing Mind map, Summarizing, Discussion, Drawing

diagrams, Expressing orally and in writing.

3. Objectives:

To understand the operating principle of squirrel cage and doubly fed induction generators.

4. Lesson Links:

What is meant by synchronous motor? Speed of induction generator.

5. Alpha Breathing : (2 Mins)

The three steps for alpha breathing are

Breathe in Breathe out Hold (Repeat the three steps for 8 times)

6. Evocation : (5 mins )

By showing videos and pictures

Annexure I

7. Introduction:( 20-25 mins) Attached as power point presentation in Annexure II

8. Brain Activation: (2 mins)

Any one of the following activities like

Right brain activities Solving puzzles Brain GYM Optical Illusions Perpetual calendar recalling

9. Survey and Reading by students: (15-18 mins)

Rao.S and Parulekar, Energy Technology Non Conventional, Renewable and

Conventional, KhannaPublishers, New Delhi, 2005

Page No : 228 - 232

10.

Discussion: ( 9 mins)

The students will be asked to discuss the relevant topic among their team/other team/Faculty. The students

those who have not taken part will be noted and kindle them to do.

11. Mind Map: (5-7 mins)

Annexure III

12. Summary: (5 mins)

Annexure IV

13. Gazing/Rote memory: (2 mins) A long and fixed look at the Mind map by the students before doing the presentation.

14. Assessment: Any one of the following activities like

Quiz Presentation by the students Match the following Short answers Objective questions / MCQ - Annexure V Group discussion

15. Learning outcomes

By learning this unit, students will be able to understand the operating principle squirrel cage and doubly fed

induction generators.

Annexure I Evocation

Annexure III Mind Map

Annexure IV Summary .Applications where high starting torque and constant speed are desired then synchronous

induction motor can be used

2. It has the advantages of both synchronous motor and induction motor. The synchronous

motor gives constant speed whereas induction motors can be started against full load torque

3. Consider a normal slip ring induction motor having three phase winding on the rotor .

4. The motor is connected to the exciter which gives d.c. supply to the rotor through slip

rings. One phase carries full d.c. current while the other two carries half the full d.c. current

as they are connected in parallel.

5. Due to this d.c. excitation, permanent poles (N and S) formed on the rotor.

6. Initially it is run as a slip ring induction motor with the help of starting resistances.

7. When the resistances are cut out the motor runs with a slip. Now the connections are

changed and the exciter is connected in series with the rotor windings which will remain in

the circuit permanently.

8. As the motor is running as induction motor initially high starting torque (up to twice full

load value) can be developed. When the d.c. excitation is provided it is pulled into

synchronism and starts running at constant speed

9. The synchronous induction motor provides constant speed, large starting torque, low

starting current and power factor correction.

Annexure V Multiple Choice Questions:

1. Induction generator requires ------------reactive power for assisting the energy conversion

process.

a. Leading b. Unity c. Zero d. Lagging

2. The advantages of seperately induction generator are

a. Needs less number of auxillary equipments b. Speed variation of prime move ris less important c. Efficiency is high d. The reactive power delivery can be ontrolled

(i) a&c (ii) a,b,d (iii) a&b (iv) a&d

3. The seperately excited induction generators are widely used in

a. Hydro generating station b. Wind mills c. Tidal power stations d. Thermal stations